United States Census Indian Schedules
There are two kinds of Indian census schedules. The kind that this page is about are the special schedules made at the same time as regular federal population schedules. If during his visit to the rest of the population, a census taker discovered a resident was an American Indian, the census taker completed a separate, additional schedule for that person. For the 1910 federal census, Indian schedules are found at the end of the regular population schedules for each county. The Indian schedules are similar but have some slightly different questions from the regular population schedules.
Another kind of Indian census was often taken of tribes, and relatively few non-Indians were counted. These were not taken at the time of regular federal censuses for everyone in the country. This type of Indian census is not described any further on this Wiki page.
Indian Census Rolls, 1885-1940
including some Vital Records
National Archives: http://www.archives.gov/genealogy/census/native-americans/
Access Genealogy: http://www.accessgenealogy.com/native/census/index.htm
Szucs, Loretto Dennis and Wright, Matthew. Finding Answers in U.S. Census Records. (Orem, Utah: 2001 Ancestry) FHL Book 973 X27s.